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slimjim Super Member
Joined: May 16, 2009 Posts: 8312 Location: Fort Worth TX
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Posted: Wed Oct 06, 2010 3:27 am Post subject: Re: Minute of Angle - All you need to know. |
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Dawgdad wrote: |
I generally will shoot at 100-200-300-500 with one scope setting and play with the ballistics program BC values until they match my trajectory. Very few bullets match published values. Again really not a huge factor out to 600 but after that... |
Dawgdad, isn't it better for VLD bullets if you figure out BC based on G7 vs G1?
Also, with an accurate enough rifle, I place the chrono at 250 or 300 yards and take the velocity readings at that range. I find it more accurate than trying to derive off trajectory drop and its easier to step-up than the tall vertical targets.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Last edited by slimjim on Thu Oct 07, 2010 10:51 pm; edited 1 time in total |
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Dawgdad Super Member
Joined: Feb 08, 2006 Posts: 1065 Location: On the Prairie
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Posted: Wed Oct 06, 2010 7:32 am Post subject: Re: Minute of Angle - All you need to know. |
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yes to both
_________________ Alcohol, Tobacco and Firearms should be a convenience store, not a government agency... |
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metz3601 Member
Joined: Oct 31, 2008 Posts: 81
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Posted: Wed Oct 06, 2010 4:50 pm Post subject: Re: Minute of Angle - All you need to know. |
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is there anything like the iSnipe program out there for a web OS phone??
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chambered221 Super Member
Joined: Aug 17, 2007 Posts: 3455 Location: Lost for good !!!
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Posted: Wed Oct 06, 2010 5:02 pm Post subject: Re: Minute of Angle - All you need to know. |
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_________________ Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!
A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
~George Washington |
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Suzanne Super Member
Joined: Jun 27, 2009 Posts: 3323 Location: Eugene, Oregon
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Posted: Wed Oct 06, 2010 5:33 pm Post subject: Re: Minute of Angle - All you need to know. |
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That's the most handy thing I've seen in those phones. I can't afford stuff like that, too many other payments to make. In my next life.......
Suz
_________________ May the moon keep you centered,
May the sun keep you dancing,
And the stars shed light on your dreams. |
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Pizzaguy Member
Joined: Oct 03, 2010 Posts: 34 Location: Oklahoma
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Posted: Fri Oct 08, 2010 11:39 am Post subject: Re: Minute of Angle - All you need to know. |
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Mil-Dots….
Ok, let’s talk about the mil-dot scope for a little while. Mil-dots are a series of “known distance” dots up and across the cross hairs of a scope. The first thing everyone needs to know about mil-dots is that they are only a known distance on ONE power setting on a variable power scope. You’ll have to read the paperwork of your scope to see what power that may be. In most cases it is max power, but there are other types. Now there are scopes that the mil-dots are the known distance on all powers, this happens when the crosshairs are set in the first focal plane of the scope. You would be able to tell this because the crosshairs would grow and shrink when you change powers. For the sake of this discussion we are using a fixed 10X scope.
Typically a scope is five mils, mil-dots are really oval not round. One “dot” is really 1/4 mil. The distance between the top of one dot and the bottom of another is 3/4 mil and the distance between the center of a crosshair and the center of a “dot” (or the center of dot to center of dot) is 1 mil. (See picture) Ok big deal, what does that mean? What it means is that the mil-dots can be used like a ruler to measure the height of a target, or if the height of the target is known then the mil-dot reticle can be used to calculate the range of the target.
Mil-dots are 1 milliradian apart. A milliradian is an angular unit of measure. 1 milliradian = 1 yard at 1000 yards and 1 meter at 1000 meters. So with our fixed 10X scope, 1 mil = 3ft at 1000 yards, so a normal white tail deer that is 36” to the shoulder is 1 mil tall you can estimate that he is 1000 yards away right? Right. So if you know the height of the target in yards and multiply that by 1000 then divide by the size in mils = the range in yards.
Now 1 mil on a USMC scope is 3.438 MOA and on an Army scope it is 3.6 MOA so if you know which scope you have use that measure. But the standard, because most people don’t know which scope they have, is to use 3.5 and split the difference (And make the math easier). So we know, because we paid attention in the minute of angle section, that 1 minute = 1” @ 100 yards, 1 minute = 2” @ 200 years and so on, therefore 1 mil = 3.5” @ 100 yards, 1 mil = 7” @ 200 yards, 1 mil = 10.5” @ 300 yards and so on.
Don’t worry I will be bringing all of these sections together before I’m done
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Last edited by Pizzaguy on Fri Oct 08, 2010 2:46 pm; edited 1 time in total |
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Pizzaguy Member
Joined: Oct 03, 2010 Posts: 34 Location: Oklahoma
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Posted: Fri Oct 08, 2010 11:44 am Post subject: Re: Minute of Angle - All you need to know. |
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The formulas got all jacked up in the post, I'll build them in a pic format in awhile and post them but for now it's...
Size of target in yards X 1000 / Size in mils = Range in yards
Size of target in inches X 27.778 / Size in mils - Range in yards
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Pizzaguy Member
Joined: Oct 03, 2010 Posts: 34 Location: Oklahoma
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Posted: Fri Oct 08, 2010 11:54 am Post subject: Re: Minute of Angle - All you need to know. |
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Another little “off to the side” way to know what power you scope must be on to be “true” and what measure it is on max magnification is to take a black marker and draw 1” lines on it and place it @ 100yrds. (Also mark 3.5”) and then play with the magnification settings until on mil is 3.5” and also learn what one mil is at max magnification. Then do the math if 1 mil is 5” at 24X @ 100yrds then at 200yrds it’s 10”, at 300yrds it’s 15”and so on.
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Dawgdad Super Member
Joined: Feb 08, 2006 Posts: 1065 Location: On the Prairie
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Posted: Fri Oct 08, 2010 2:33 pm Post subject: Re: Minute of Angle - All you need to know. |
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I thought a minuet was a kind of classical music?
_________________ Alcohol, Tobacco and Firearms should be a convenience store, not a government agency... |
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Pizzaguy Member
Joined: Oct 03, 2010 Posts: 34 Location: Oklahoma
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Posted: Fri Oct 08, 2010 2:48 pm Post subject: Re: Minute of Angle - All you need to know. |
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Dawgdad wrote: |
I thought a minuet was a kind of classical music? |
But it's part of the "don't ask, don't tell" thing, how do you know about it?
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Dawgdad Super Member
Joined: Feb 08, 2006 Posts: 1065 Location: On the Prairie
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toddco Rookie Member
Joined: Sep 09, 2009 Posts: 20
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Posted: Sat Oct 16, 2010 8:45 am Post subject: Re: Minute of Angle - All you need to know. |
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All cool info. Would you happen to know anything about cosine angles? Also, another very good and user friendly app for the iphone and shooting enthusiast is the app called: Bullet Flight. In this app you enter your rifle/pistol information, load information, zero sight in, distance to target, wind, hit enter and it tells you how many moa to adjust for your shot. It seems very accurate if you put the correct information in to it. I have also read somewhere that 1\4" click moa scopes are not quite 1\4", is this correct?
Thanks,
Toddco
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Elvis Super Member
Joined: Jul 27, 2008 Posts: 9232 Location: south island New Zealand
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Posted: Sat Oct 16, 2010 3:20 pm Post subject: Re: Minute of Angle - All you need to know. |
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todco REREAD the last 2 lines of the first paragraph and the 3rd. my personal experience tells me to try out when sighting in as all scopes are slightly different. some adjust bang on and others are nothing like what they say. some dont move much then jump waaay over. I always adjust the amount I think is right then tap firmly on the turrents of the scope fire anothr group and have a look where the holes are. I also move my scopes 12 click one way then back 2 the other not just 10 the way I want as a engineer buddy who taught me heaps about shooting said to. It works for me so I do it.
_________________ You shot it You pluck it !
Them who eats the most duck eats the most feathers! |
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Pumpkinslinger Super Member
Joined: Sep 22, 2007 Posts: 5000 Location: NC foothills
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Posted: Sat Oct 16, 2010 6:42 pm Post subject: Re: Minute of Angle - All you need to know. |
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After making any scope adjustments I bump the butt of the rifle against something hard, like the bench top, to help it settle in. Then, as Elvis says, shoot another group.
_________________ Mike
"I ain't no better than anybody else, and there ain't nobody better than me!" Ma Kettle |
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slimjim Super Member
Joined: May 16, 2009 Posts: 8312 Location: Fort Worth TX
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Posted: Sun Oct 17, 2010 5:32 am Post subject: Re: Minute of Angle - All you need to know. |
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At the range yesterday with a friend. He put in 5 clicks of windage in stages with a Leupold scope for 100 yards and groupings didn't move. Finally left well enough along. It was only 1/2 inch to the right. Fired many groupings. Seems one important aspect of scope quality can be measured by how precise the adjustments works. I haven't seen to many that adjust as they claim.
_________________ "To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt
"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein |
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